1. Field of the Invention
The present invention relates to a substrate processing apparatus, and particularly to a substrate processing apparatus having an upper lid that engages a processing vessel to define a substrate processing chamber.
2. Description of the Related Art
In a semiconductor device manufacturing method for manufacturing a semiconductor device from a silicon wafer (hereinafter simply referred to as “wafer”), the following steps are repeatedly carried out in a sequential manner: a film formation step of forming a conductive film or an insulating film on the surface of the wafer using CVD (Chemical Vapor Deposition) or the like, a lithography step of forming a photoresist layer having a desired pattern on the formed conductive film or insulating film, and an etching step of using the photoresist layer as a mask to shape the conductive film into a gate electrode or form a wiring groove or a contact hole in the insulating film by using plasma generated from a process gas.
For example, in a certain semiconductor device manufacturing method, a polysilicon layer formed on a wafer is etched in some cases. In this case, a deposit film primarily made of SiO2 is formed on the side surfaces of a trench (groove) formed in the wafer.
Since the deposit film may cause problems in the semiconductor device, such as conduction failure, the deposit film must be removed. As a method for removing the deposit film, there is known a substrate processing method for carrying out COR (Chemical Oxide Removal) and PHT (Post Heat Treatment) on the wafer. In COR, SiO2 in the deposit film chemically reacts with gas molecules to form a product, and in PHT, the wafer that has undergone the COR is heated to vaporize and sublimate the product formed on the wafer in the COR chemical reaction. The product is thus removed from the wafer.
As a substrate processing apparatus that carries out the substrate processing method including the COR and PHT steps, there is known a substrate processing apparatus including a chemical reaction processing apparatus and a thermal processing apparatus connected to the chemical reaction processing apparatus (see, for example, Japanese Laid-Open Patent Publication No. 2005-39185 (corresponding to U.S. Laid-open Patent Publication No. 2004/0262254)).
The above chemical reaction processing apparatus typically includes a processing chamber (hereinafter referred to merely as “chamber”) that accommodates a wafer, a shower head that serves as a gas supplying portion for supplying hydrogen fluoride gas or the like as a process gas into the chamber, and a mounting stage on which the wafer is mounted. The shower head is disposed in such a way that it faces the wafer mounted on the mounting stage. On the other hand, the chamber has an openable/closable upper lid. The shower head is incorporated in the upper lid of the chamber, and an introduction tube through which the hydrogen fluoride gas or the like is introduced into the shower head is connected to the upper lid of the chamber.
In the hydrogen fluoride gas, hydrogen fluoride molecules are clustered, that is, hydrogen fluoride molecules are linearly bonded. Dissociation of the hydrogen fluoride molecule clusters, which depends on the change in temperature and pressure, causes abrupt decrease in temperature, sometimes resulting in liquefaction of the hydrogen fluoride gas in an introduction path that communicates with the chamber of the chemical reaction processing apparatus. It is noted that hydrogen fluoride gas boils at 19.5° C. (near room temperature) at atmospheric pressure (760 Torr), and liquefies at room temperature at or near atmospheric pressure.
In a conventional chemical reaction processing apparatus using hydrogen fluoride gas described above, the temperatures of all members that form the introduction path through which the hydrogen fluoride gas is introduced into the chamber are controlled to prevent liquefaction of the hydrogen fluoride gas in the introduction path.
However, in and around the upper lid of the chamber, the introduction tube described above is routed in a complicated manner. To control the temperature of the entire introduction tube including a portion thereof in the vicinity of the upper lid, the number of the parts used for temperature control increases. Further, to open and close the upper lid of the chamber, it is necessary to configure the introduction tube connected to the upper lid of the chamber to be detachable, and designing a detachable introduction tube requires extra parts.
Therefore, when the introduction tube is connected to the upper lid of the chamber, the number of parts used to form the substrate processing apparatus increases.